FR2552487A1 - DRILLING DEVICE WITH SIMULTANEOUS SINKING OF THE BOREHOLE - Google Patents

Abstract

A. DEVICE FOR DRILLING SOILS AND ROCKS. B. DEVICE CHARACTERIZED IN THAT THE GUIDE 10 IS NON-ROTATIONALLY CONNECTED TO THE ENERGY TRANSFER UNIT 9, AND THAT THE DRILL BIT 11 IS MOUNTED IN LIMITED ROTATION ON THE END OF THE TRANSFER UNIT D 'ENERGY 9, THE ROTATION ANGLE AMOUNTING TO AT LEAST 90, PREFERREDLY 180. C. THE PRESENT INVENTION AIMS, AMONG OTHER THINGS, TO REDUCE THE COST OF DRILLING.

Description

255248?

  Drilling device - with simultaneous sheathing of the borehole.

  The invention relates to a soil and rock drilling device, for percussion-rotating drilling operations, or only for rotary drilling operations, with simultaneous sheathing of the borehole by a tube. The drilling of holes with simultaneous sheathing of the borehole by a tube is a complicated undertaking because, among other reasons, the formations to be drilled are very varied and complex When drilling the water well, it is desirable in most In this case, the drillholes must be sheathed over a large part of their vertical section, and in addition, it must be possible to penetrate into all types of formation, such as quicksand; hard, viscous and swollen argan formations; alluvial conglomerates with small pebbles or pebbles; moraines with small and large pebbles; fissured rock areas, etc. It is also desirable to have good drilling properties in hard rock, as it is often necessary to drill holes over considerable lengths in the rock, for example in regions

  o As a result of geological displacements, clay layers may exist underneath.

  Drilling devices for the mentioned purposes

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  For example, drilling rigs must be able to grind rocks and stones efficiently and with minimum intrinsic wear and / or to penetrate hard, swelling clay. Drilling device must also be designed to effectively transport the drilling debris to the surface, through the cladding tube while protecting the tube against damage In particular, the loads acting on the lower end of the tube The cladding should be limited so that even plastic tubes can be used. The lower end of the cladding tube is particularly subject to tension, partly as a result of the lateral forces emanating from the guide, which tend to break the tube and drive the tube. borehole 15 in an oblique direction, and partly as a result of wear due to crushing of coarse debris or erosion of finer debris between Finally, the drilling device must be easy to handle, simple and, above all, reliable, so as to ensure, for example, that the drill bit or crown does not lock in its eccentric drilling position or unscrews and falls into the hole while the wick is being removed

  and the drilling device raised through the hole.

  The drilling devices previously proposed for use with cladding tubes generally require the presence of a circular guide aligned with the center of the cladding tube, as well as a separate pilot drill bit, to provide satisfactory guidance of the cladding tube. An example of a device of this type is described in Swedish Patent No. 377,706. Other drilling devices previously proposed to meet the stated objectives, including a drill bit or drill bit which is fixed relative to the drill rod, and an eccentric guide which is mounted for limited rotational movement -3 Examples of such devices are described in Swedish patents No. 188 739 and No. 212 006 Rotating eccentric guides of this type are nevertheless easily blocked by debris, thus preventing the drill bit from being removed after the completion of the drilling operation An alternative is to See the guide so that it is impossible to transport debris through the cladding tube. see the patent

Swedish city number 212 006.

  The object of the invention is to better meet the mentioned requirements than the current drilling devices in

  allowing among others to reduce the cost of drilling.

  The device for drilling soils and rocks with simultaneous sheathing of the borehole by a sheath tube according to the invention comprises an energy transfer member in the form of a driving hammer, a drilling or a similar element; a guide 20 adjacent to the member, an eccentric drill bit mounted on one end of the energy transfer member which, relative to the guide, can be in limited rotation between two end positions, a das end positions constituting a extended drilling position in which the cutting portion of the drill bit produces, opposite the cladding tube, a hole whose diameter is greater than the outer diameter of the cladding tube, and the other end position of rotation constitutes a retracted position wherein the drill bit, in common with the guide, is disposed within the cladding tube and can be removed through this tube, the originality of which is that the guide is

  non-rotational connection to the energy transfer member, and that the drill bit is rotatably mounted

  limited on the end of the energy transfer member, the angle of rotation amounting to at least 90,

preferably 180.

  In addition, in a device according to the invention, the periphery of the guide is provided with a surface which bears against only that part of the inner surface of the cladding tube which is diametrically opposed to the most eccentric part of the wick. in its extended position, and there is a gap between the periphery portion of the guide diametrically opposed to the guide surface and the cladding tube, this gap allowing the energy transfer member to be moved eccentrically to this gap

  when the drill bit is in its retracted position.

  Moreover, in a device according to the invention, during the drilling operation, the central axis of the guide surface is displaced, so that the central axis of the energy transfer shaft is disposed of. eccentrically between the central axis of the cladding tube and the

  most eccentric part of the drill bit.

  Moreover, in a device according to the invention, the guide surface bearing against the guide tube is in the form of a helicoidal piece, positioned to lift the debris by helical movement, upwards in the tube during the drilling operation with a normal direction of rotation. In addition, in a device according to the invention, the drill bit is provided with a rod having on its side a peripheral portion which guides against the inner surface of the sheath tube in the drilling position, this peripheral portion being placed on the same side as the guide surface when the drill bit is in

its retracted position.

  Moreover, in a device according to the invention, the drill bit is provided with central cutting edges disposed on the portion of the bit which is diametrically opposed to its most eccentric part, these cutting edges are arranged near the center. of the borehole, through which the ridges develop a guiding force which will press the most eccentric portion of the drill bit against the periphery of the borehole for

the drilling operation.

  Moreover, in a device according to the invention, the periphery of the most eccentric portion of the drill bit rests on a circle which is concentric with the borehole during the drilling operation, and a set of cutting edges. is planned for cutting on the periphery

of the borehole.

  The drilling device according to the invention comprises an energy transfer member in the form of a drill shaft or the like; an asymmetrical guide on this organ; and a drill bit or drill bit mounted on the guide for limited rotational movement. An end position of rotation of the drill bit is a prolonged, eccentric drilling position in which the drill bit produces, opposite the cladding tube, a hole whose diameter is greater than the outside diameter of the cladding tube The other end position is a retracted position in which the drill bit, in common with the guide, is arranged inside the cladding tube and can be The drilling device can be coupled to a succession of drill rods which transmit the rotational movement and, where applicable, the percussion energy from a percussion apparatus. placed outside the hole, or it can be coupled directly to a hammer placed in the hole,

in this hole.

  The drilling device according to the invention differs from known devices of this type mainly in that the guide of the drill bit or drill bit is connected without the possibility of rotation to the energy transfer member (the drill shaft). and since the drill bit is mounted in limited rotation at the end of the energy transfer member, the angle of rotation amounts to at least 90, preferably 180. the peripheral portion of the guide, resting against the inner cladding surface, is placed diametrically opposite to the portion of the drill bit having the greatest eccentricity with respect to the center line of the cladding tube. The special design of the guide between other, provides space for considerable eccentric displacement of the drill bit, which in turn contributes to an additional advantageous shape of the geometry of the drill bit.

cutting the drill bit.

  Other features and advantages of the invention will appear in the description below of an embodiment illustrated in the accompanying drawings, wherein FIGS.

  Figure 1: An axial sectional view of the drilling device, taken through the most eccentric portion of the drill bit, presented in the drilling position; Figure 2: a sectional view similar to that of Figure 1, but with the drilling device shown in its retracted position, that is to say with the drill bit turned 180 and returned to the cladding tube; Figure 3: a radial section view of the guide, taken along the line 3-3 of Figure 1; Figure 4: a radial sectional view of the rod portion of the drill bit and the eccentric axis of the guide, along the line 4-4 of Figure 1; Figure 5 is an end view of the drill bit of the drill bit, and the sheath tube, in the direction 5-5 of Figure 1; FIG. 6 is an end view of the drill bit of the bit and the sheath tube in the direction 6-6 in FIG. 2 and with a rotation of a half revolution so as to allow an easier comparison with the position

illustrated in Figure 5.

  In the figures, the reference 7 designates the theoretical contour of the drilled hole; 8 denotes the cladding tube; 9 denotes the lower part of the drill shaft; 10 denotes the guide; and 11 designates the drill bit or drill bit. As shown in FIG. 1, the guide 10 comprises an upwardly extending axis which is narrower than the main part of the guide. This axis is provided with an external thread adapted to a corresponding threading made in a cavity of the drilling shaft 9, thus allowing the guide 10 and the drill bit 11 attached thereto to be removed from the shaft 9, as and when necessary This threaded connection can not rotate under normal conditions, it is that is, the connection can be released only with the aid of a tool after the drilling device has been removed from the borehole or borehole. The guide also has a cylindrical shaft extending downwards, which is also narrower than the main portion of the guide Drill bit 1 it is provided with a hollow shank which surrounds the shaft and is attached thereto so as to allow only limited rotational movement of the shaft.

  the wick around the tree extending down.

  As shown in FIG. 1, the guide 10 is formed such that in the drilling position the shaft 9 is not in alignment with the center of the sheath tube 8, but is displaced

  in one direction to the portion of the drill bit that exhibits the highest degree of eccentricity This movement of the bit, among others, allows a more even distribution of the load on the head of the drill bit in the drilling operations. percussion.

  The arrows 12 in FIGS. 3-5 illustrate the direction of rotation during the drilling operation. In FIG. 3, the arrow 13 designates the force that presses the guide against the sheath tube, as a result of the torque required for the rotation of the wick. The arrow 14 indicates the force that presses the guide against the cladding tube, resulting from the pressure of the wick on the peripheral wall of the hole. The arrow 15 indicates the resultant of the forces 13 and 14. circular arc of the guide having a surface which bears against the cladding tube during the drilling operation References 17 and 18 designate sectors of the guide which, during drilling, have a gap of uniform width with the tube 25 Cladding 19 denotes an arcuate sector of the periphery of the guide which is separated from the cladding tube by a variable width gap, the width of the gap in the central region of this sec being greater than that presented by the guide sectors 17 and 18, and the contour of this sector 19 corresponds to the inner profile of the cladding tube when the wick occupies

  its retracted position in the cladding tube.

  In FIG. 4, references 20 and 21 denote wick shank sectors which, during the drilling operation, have, with respect to the cladding tube, gaps of uniform width, identical to those of sectors 17 and 18 on the guide. The reference 22 designates an arcuate sector on the periphery of the rod, this sector making it possible, during drilling, to provide additional guidance with respect to the guide tube. The reference 23 designates an arcuate sector of the periphery of the rod. rod which has with respect to the cladding tube a gap of variable width, the width of this interstice in the central zone of the sector being greater than that of the interstices presented by the respective sectors and 21, and the contour of this sector being adapted to the inner contour of the cladding tube when the drill bit is in its retracted position inside the cladding tube. Locust in the form of a cylindrical circular rod, mounted in the drill bit shank Reference 25 designates a groove in the eccentric shaft of the guide, receiving the locking element 24 and formed so that the drill bit 20 can 180 rotation, that is between the previously mentioned drilling position and the retracted position also mentioned, but being axially locked When assembling the drilling device, the locking element can be fixed The reference numeral 26 designates an air flushing channel which connects the central flushing channel 27 to the groove 25 and the bearing gaps between the rod.

  wick and guide, to facilitate lubrication and cleaning.

  As shown in Fig. 1, under the groove 25 there are two other grooves, corresponding to the groove, which are intended to cooperate with other locking elements in the wick rod, as previously described with reference to the locking element 14, so

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  that for safety reasons, the loads are distributed over a number of locking elements and the corresponding grooves. As shown in FIG. 1, the mentioned central flushing channel 27 extends through the drill bit, the guide and the drill shaft. An unrepresented control valve is arranged at 29 on the bit 11. 28 'intended to place sealing rings with lips 10 facing outwards are mounted in the wick shank and the drill shaft, respectively As for the control valve, these seals allow the air driven from exit the central flushing channel while avoiding the penetration of water and drilling debris. In FIG. 5, the references 30-35 denote hard metal inserts in the non-circular drill head of the bit, this head performing the actual work of drilling / grinding stones.

  inside which the central cutting insert 30 works.

  The reference 37 designates the circle within which the two inserts 31 and 32 work, this circle being located outside the circle 36. The prior cutting inserts 33, 34 and 35 work between the circle 37 and the periphery 25. Thus, the number of cutting inserts is approximately proportional to the areas between these circles, resulting in uniform wear and therefore the best possible use of hard metals Reference 38 indicates the maximum eccentric extension that can be conferred to the drill head per se while remaining entirely indoors

  of the sheath tube in the position of the wick (see 6).

  This maximum possible high eccentricity was not used, and instead it was possible to cut a segment in an arc so that the most eccentric periphery of the drill head produces a sufficiently large hole. relative to the outer diameter of the cladding tube, and most importantly, it provides a non-peripheral portion of the drill head which acts against the periphery of the hole or bore and allows the establishment of a large number of inserts in metaldur on the periphery, which allows to maintain the diameter of the hole for a much longer duration, despite wear on the drill head, that is to say to prolong the life of the wick Diameter wear is often A factor which limits the service life of the drill bit A longer peripheral portion and more peripheral cutting inserts also provide a more smooth, less jerky rotational movement. designates a front shoulder that connects the most eccentric portion of the drill head to the outer diameter of the hole or bore in the direction of rotation. As a result of the discontinuous transition to the front shoulder, a contact wedging with the borehole This avoidance creates a "crushing zone". Avoiding the creation of such a "crushing zone" is an important contribution to the reduction of peripheral wear on the head of the machine. drilling, and torque needed for rotation of the drill head; this results in a

  reduced tendency to coincenent, thus a less jerky rotation of the head.

  The three cutting inserts 30, 31 and 32 are placed on one face of the drill head and are positioned obliquely to form a cone at the center of the borehole. This results in reaction forces which help to support the horizontal cutting inserts 33, 34 and 35 on the other side of the drill head, towards the periphery of the borehole, and guide the bit. This reduces forces 13 , 14 and 15, thus relieving the guide and in addition, reduces wear and allows a more uniform rotation As a result,

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  the support surface 16 of the guide must not be especially large It must nevertheless extend in the peripheral direction approximately to the lines of force 13 and 14 in the respective directions, since these forces can vary greatly in amplitude. This peripheral part of the guide may be in the form of a narrow portion which is spirally or obliquely disposed so as to move the debris by a helicoidal movement of the bit during drilling Although the guide peripheral portion 22 of the The wicking rod is in fact superfluous when drilling a homogeneous material, it ensures a smooth and uniform rotation in the event of irregularities in the foundations to be drilled. For this reason, this peripheral part also has the shape of a portion. narrow, oblique or spiral When the wick is in the drilling position, the interstices 20 and 21 on the wick shank and the interstices 17 and 18 on the

  guide, form a continuous length of interstices which restricts the dimensions of the particles that can pass.

  For other reasons, the open space around the guide and the wick shaft should be as large as possible, so as to increase the capacity of the drilling device to evacuate the debris, and thus the portions 16 and 22 are

preferably narrow.

  The main construction described above, with guide elements 16 and 22 distributed between the guide and the wick, respectively, allows extensive eccentric adjustment to the drill bit, which in turn makes possible the favorable formation mentioned. cutting geometry, without jeopardizing the necessary dimensioning of the eccentric shaft of the guide or rod

  wick, with respect to their mechanical stress.

  The angular difference between the central part of this part of the periphery of the guide which bears against the inner surface of the sheath tube, and the central part of the most eccentric part of the wick, measured from the first to the last, in the direction of rotation of the wick during the drilling operation, is preferably less than 180, and more preferably between 100 and 170, as shown

  the description below in relation to the direction of the

  Forces 13 and 14 The guide is preferably formed such that in the drilling position it rests on the inside of the cladding tube, along a sector which corresponds to a central angle of about 50-150 mm. Finally, the peripheral portions of the guide and the wick stem which, in the retracted position of the wick, are diametrically opposed to the most eccentric portion of the wick during drilling, are preferably designed to permit of such amplitude between the drilling position of the wick and the retracted position thereof, that a peripheral portion of the most eccentric portion of the wick in the drilling position can be sucked against the inner face of the wick. borehole along an area that corresponds to a central angle of over

   , the wick and the guide in the retracted position being also arranged inside the cladding tube.

  In the embodiment described above the wick of

  Drill is provided with six hard metal cutting inserts.

  The three peripherally placed cutting inserts can be placed at different heights, so as to achieve a uniformly distributed load and cutting volume between these cutting inserts during the downward spiraling movement thereof during the drilling operation. The wick may have hard metal tips instead of hard metal cutting inserts, which number is slightly greater than that of the inserts of the described embodiment. When drilling is purely rotational, it is possible

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  to give the cutting inserts a shape that looks more like a flattening wick, a design called

  dredge bit, or these inserts can be replaced by one or more toothed cylinders, a design called cylinder wick.

Claims (1)

1 Apparatus for drilling soil and rock, with simultaneous sheathing of the borehole (7) by a cladding tube, the device comprising an energy transfer member (9) having the shape of a hammer of sink drilling, a drill shaft or the like; a guide (10) adjacent to the member (9); an eccentric drill bit (11) mounted on one end of the energy transfer member (9) which, relative to the guide (10), can be in limited rotation between two end positions, one of the end positions constituting a extended drilling position in which the cutting portion of the drill bit (11) produces, opposite the sheathing tube (8), a hole whose diameter is greater than the outside diameter of the cladding tube (8), and the other end position of rotation constitutes a retracted position in which the drill bit (11), in common with the guide (10), is disposed inside the cladding tube (8) and can be withdrawn through this tube, characterized in that the guide (I 0) is non-rotatably connected to the energy transfer member (9), and that the drill bit (11) is mounted in limited rotation on the end of the energy transfer member (9), the angle of rotation is amount to at least 90, preferably 180. 2 Device according to claim 1, characterized in that the periphery of the guide (10) is provided with a surface (6) which bears against only that part of the inner surface of the cladding tube (8) which is diametrically opposed to the most eccentric portion of the drill bit (11) in its extended position, and that there is a gap (19) between the portion of the periphery of the guide (10) diametrically opposed to the guide surface (16) and the cladding tube (8), this gap (19) allowing the energy transfer member (9) to be eccentrically displaced to this gap (19) when the drill bit (11) ) is in its retracted position. 3 Device according to claim 1 or 2, characterized in that during the drilling operation, the central axis of the guide surface (16) is displaced, so that the central axis of the transfer member of energy (9) is eccentrically disposed between the central axis of the cladding tube (8) and the most eccentric portion of the drill bit (11). 4 Device according to any one of claims 1 to 3, characterized in that the guide surface (16) bearing against the guide tube (8) is in the form of a helical piece, positioned so as to remove the debris per helicoidal movement, upwards in the cladding tube (8), during the drilling operation with a normal rotation direction. Device according to any one of claims 1 to 4, characterized in that the drill bit (11) is provided with a rod having on its side a peripheral portion (22) which guides against the inner surface of the tube. sheathing (8) in the drilling position, this peripheral portion (22) being placed on the same side as the guide surface (16) when the drill bit (11) is in its retracted position. 6 Device according to any one of claims 1 to 5, characterized in that the drill bit (11) is provided with central cutting edges (30, 31, 32) arranged on the part of the bit (11) which is diametrically opposed to its most eccentric portion, these cutting edges (30, 31, 32) are disposed near the center of the borehole (7), through which the ridges (30, 31, 32) develop a force guide which will press the most eccentric portion of the drill bit (11) against the periphery of the borehole (7) during the drilling operation. 7 Device according to any one of the claims   1 to 6, characterized in that the periphery of the most eccentric portion of the drill bit (11) rests on a circle which is concentric with the borehole during the drilling operation, and a set of cutting edges (33, 34, 35) is provided for cutting at the periphery of the drilling hole (7).